Shot pattern control device for shotguns



March 3, 1953 w, RQPER r 2,629,958

SHOT PATTERN CONTROL DEVICE FOR SHOTGUNS Filed July' 29, 1950 FIG. I

lll

INVENTORS Mu rffifi'fiopm ,q/vo FEEDER/CA I WING/1r BY *WM ATTORNEYS Patented Mar. 3, 1953 SHOT PATTERN CONTROL DEVICE FOR SHOTGUNS Walter F. Roper, Longmeadow, and Frederick J. Wright, Chicopee, Mass, assignors to Savage Arms Corporation, Utica, N. Y., a corporation of Delaware Application July 29, 1950, Serial No. 176,586

2 Claims. (CI. 42-79) This invention relates to improvements in shot pattern control devices for use on shotguns.

A variety of different devices have been provided on shotguns to reduce recoil and to control the pattern of the shot mass for different conditions ofhunting and competitive shooting. These different constructions may have expansion chambers providedwi-th gas vents, compression chambers, recompression chambers, and choke chambers to be mounted singly or in combination and in varying forms and arrangements on shotgun barrels. Such devices generally comprise cylindrical members for attachment on the muzzle end of a shotgun barrel, or are formed at the end of the barrel itself and may be a recoil reducing compensator alone, a fixed or a variable shot pattern control choke, or a compensator and a choke arranged in tandem.

It is an object of this invention to provide, in a short pattern control device of the type having a variable choke mechanism, an improved and novel means for accurate adjustment to the degree of choke desired.

Another object of the invention is to provide an adjustable choke measuring device of simple yet rugged design so that the device may be more conveniently and readily installed in operative condition on the barrel without the degree of precision work previously necessary.

A further object is to provide means in the variable choke device for resisting inadvertent displacement of a selected degree of choke once the variable choke mechanism has been selectively set.

These as well as other objects and advantages of the invention will be apparent in the following specification and accompanying drawings, in which:

, Fig. 1 is a top plan on enlarged scale of a device embodying, the invention and fixed on the end of a shotgun barrel;

Fig. 2 is a longitudinal section of the device on line 2-2 of Fig. 1; and

Figs. 3 and 4 are detailed views on lines 33 desired. Choke shell 2 at its innermost end is provided with a tapered cylindrical wall portion '5 providing a compression chamber, the function of which is to impede the powder wad and to regroup the shot traversing the expansion chamber after the shot mass has been expanded by the escape of part of the expanding gases through vents B of the expansion chamber.

As will be appreciated, after the shot mass leaves the compression chamber it enters the choke section provided by the shell 2. The shell is for-med with a plurality of annularly arranged resilient segments 1. By constricting segments 1 at the outer ends thereof varying degrees of choke may be obtained. The shot pattern may thus be varied to make one gun suitable for use under different shooting conditions.

Endless screw threads 9 are provided on the outer surface of shell 2 and are spaced from the inner end thereof for cooperation with interior threads 10 of an imperforate cylindrical adjusting sleeve II. The sleeve fits over the forward end of shell 2 and is turned on threads 9. The end face I2 of the sleeve lies opposite a forwardly facing annular abutment l3 at the inner end portion of shell 2. The inner forward end portion of sleeve l I is formed with a shouldered cam surface [4 which cooperates with beveled shoulders t5 at the-outer ends of segments 1 so as to constrict said segments for a choking effect when the sleeve is turned on threads 9 for inward movement on the shell 2.

A circumferential series of detent ridges, as are provided by the knurling at 16, encircles the exterior of sleeve ll closely spaced from the face 12 (see Figs. 2 and 3). The knurling is recessed in a groove in the outer Wall surface of the sleeve. At an appropriate location between two longitudinally disposed ridges of the knurling l6, as will be described, there is engaged an inwardly hooked end ll of an annular spring steel clamp ring band is received in the groove to lie with its outer surface flush with the surface of the sleeve. The band encircles the knurling and resiliently holds one or more detent elements as balls IS in o penin-gs provided, as shown, in the wall of sleeve H. The balls [9 project outwardly of the ridges I 6 and to a slight degree inwardly of the adjacent inner sleeve Wall to engage a knurled circumferential surface-20 having longitudinally disposed ridges on an annular raised rib 2| (see Fig. 2) on shell 2. The openings for the balls 19 are restricted at their inner ends to retain the balls in the openings. Rib 2| is slightly spaced from abutment l3 and lies intermediate said abutment and threads 9. The engagement of the ball between ridges of the knurling 29 provides a releasable detent for the positioning of sleeve H on shell 2 and resists inadvertent rotation of these members on threads 9 and H). The detent is designed to resist inadventent displacement of a selected position of the choke once the choke adjusting sleeve H has been selectively set as will be described. The sleeve H on its outer surface is circumferentially knurled at 22 for a finger grip to turn and adjust sleeve I l on shell 2 against the resistance of the ball detent.

An indicator scale is provided for setting the degree of choke desired and consists of a series of circumferentially spaced indicia marks 23 on band l8. An indexing mark 24 is provided on the top center line of the compensator 1 immediately adjacent the abutment 13.

For correct alignment of the scale marks of clamping band l8 with index 26 so that sleeve I I may be set accurately to any desired degree of choke, sleeve II is turned inwardly on the shell and the segments 1 constricted tightly on a plug gauge so that a condition of full choke exists in the shell. The band 18 is then snapped into the roove on the sleeve substantially covering the ridges 16. The mark 23 which indicates full choke is then longitudinally aligned with the index 24 and the hook I] is engaged'to hold the band securely positioned.

The mark 23 aligned with index 24 is distinguished from the other marks 23 by a legend such as Full indicating the position of full choke or full bore condition. It will be understood that as is common in variable .choke devices threads 9 .and I are provided with a pitch to give in one complete revolution of the sleeve all the various degrees of choke from full choke to full bore condition of the device. The other scale marks are previously calibrated on band l8 and may be appropriately marked to indicate the degrees of choke obtained when the shell is turned to bring said marks into alignment with index 24. The band [8 thus provides a choke indicator which is quickly and easily set and which is at the same time firmly locked in position by engagement of the hooked end between ridges I 6, This method of providing the indexed choke mechanism eliminates much precision work previously necessary in such devices.

n h drawin s the marks .23 for other than full choke are shown as indicated by numerical ymbols as in a s ri s from one to seven to indiat vari u degr of m dified ch kin positions ranging from full choke to full bore. It will be understood, however, that there may be a greater or lesser number of marks 23 and the marks themselves may be in any desired terms such as the number of yards at which the shot mass will provide a given diameter of shot pattern at the various degrees'of choke. It will also be, understood that the indexing means for registration of the various indicator marks may be otherwise provided for on the stationary member of th d v a ight being one xamp f such anv alternative reference point sometimes used.

What is claimed is:

1. In a shot pattern control device for gun barrels, of the type having a choke shell with the forward portion thereof longitudinally slotted to form longitudinal segments and an imperforate adjusting sleeve fitted over and bearing against the forward segmented end of the shell, said sleeve being in threaded engagement; with the she l fo l ngi udinal movement cnsaid shell to contract the forward end thereof; a circumferential groove in the exterior wall of said sleeve adjacent the inner end thereof, a series of knurled ridges in said groove, an opening through the sleeve wall intersecting said groove and having a restriction at its inner end, a detent element in said opening projecting inwardly beyond the interior cylindrical surface of said shell adjacent the restricted end of the opening and projecting outwardly into said groove beyond said ridges, a spring clamp band received by said groove and urging said detent inwardly of said opening, .said shell having a knurled circumferential surface for registration with the inner end .of said detent element and releasably receiving the same in any position of choke adjustment to which said sleeve is turned, said clamp band on its outer surface having calibrated indicator'marks thereon and for alignment therewith an indexing means on said shell, and means to releasably lock said clamp band in said groove in any desired position ciroumferentially of said shell.

2. In a shot pattern control device for gun barrels, of the type having a choke shell with the forward portion thereof longitudinally slotted to form longitudinal segments and an imperforate adjusting sleeve fitted over and bearing against the forward segmented end of the shell, said sleeve being in threaded engagement with the shell for longitudinal movement on said shell to contract the forward end thereof; a multiplicity of closely spacedrecessed portionscircumferentially arranged in a series encircling the exterior of the shell rearwardly of the inner end of said segments. a multiplicity of closely spaced recessed portions circumferentially arranged in a series encircling the exterior of said sleeve in corresponding position to said series .on the shell, a movable detent element mounted in the wall of said sleeveremovably engaging. at its inner end one of the recessed portions of said shell and intersecting at its outer end the series of recessed portions on said sleeve, 2. split ring spring clamp member having a hook at one end removably seated in one'of said recessed portions of the sleeve and being clamped over said series of recessed portions with the ring member retaining the detent element pressed against said shell, said split ring member having spaced calibrated indicator marks thereon and for alignment therewith an index reference mark on said shell, whereby when said shell is contracted against a full choke gauge said split ring may be clamped around said sleeve over the recessed portions thereof with a full choke indicator mark of the split ring in registration with said index reference mark of the shell and with said hook engaging the recessed portion adjacent thereto in said registered position of the clamp member.

WALTER F. .ROPER. FREDERICK J. WRIGHT.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS 

